A pacemaker of this type is known for example from EP 0 882 469 B1. A pacemaker electrode is known for example from DE 33 00 050 C2.
Implantable pacemakers are operated either with unipolar pacemaker electrodes or with bipolar pacemaker electrodes. In the case of a unipolar electrode, the electrode tip of the pacemaker electrode operates as a cathode and the pacemaker housing as an anode. The bipolar systems match the unipolar systems insofar as they also operate with a cathodic electrode tip. In contrast to the unipolar systems, however, in bipolar pacemaker electrodes an anode is additionally arranged in the distal area of the electrode. Pacemaker electrodes which serve to transmit stimulation pulses from a pulse generator arranged in the pacemaker housing to the heart, in particular to the atrium and/or to the ventricle, can be advanced with the aid of an introducer through a vein to the heart, it being possible for this procedure to be monitored under X-ray fluoroscopy.
Both in the case of unipolar pacemaker electrodes and in the case of bipolar pacemaker electrodes complications can arise if the patient wearing the pacemaker is exposed to a strong magnetic field. Strong magnetic fields of up to 7 Tesla occur in particular in magnetic resonance devices. If the magnetic field is changed and/or the pacemaker electrode is moved in the magnetic field, then currents are induced which may lead to intense heating of the pacemaker electrode and to irreversible tissue damage. For this reason, patients with a pacemaker according to the prior art cannot be examined in magnetic resonance devices.